You’ve never seen a Terminator quite like the REV-9 from Terminator: Dark Fate. The new killing machine features an endoskeleton that looks a lot like the familiar T-800 model from the original Terminator films, but it’s covered in a liquid metal ectoskeleton, like the liquid metal T-1000, which can jump off its frame and split the Terminator in two.

This week we talked to Terminator: Dark Fate star Gabriel Luna, who plays both versions of the REV-9 and had his own insights into the character’s construction, even going so far as to tell the production that one element of the new villain’s look needed to change.

“I really love the new design. At first we were all questioning the gap in the skull,” Luna reveals. “You know, there’s like a void there. And at first we were like, what?”

“But then the more I looked at it I fell in love with it. I mean, of course. There’s no brain there. Why he need a cranial cavity to protect? He wouldn’t need it. He’s more efficient than that,” Luna explains.

It’s a clever idea that implies that, unlike the T-800, which kept its CPU in its skull like a human being, the REV-9 keeps it somewhere else to be a less obvious target.

“Right, exactly. So I think it might be housed somewhere in the thorax, maybe,” Luna says. “But I do really love the new design. I just think it’s mean-looking.”

But that doesn’t mean Luna didn’t think there was one part of the REV-9’s design that needed a little tweaking.

“At one point they were considering having it have these really purplish pale blue kinda eyes, and I said no man, they have to be red. Or at least in kill mode they have to turn red,” Luna reveals.

“Tim gave me these really great posters, all this concept art to hang in my trailer, and they all had these blue globs, orbs, and it looks cool but it just wasn’t ‘Terminator.’”

Terminator: Dark Fate is now playing in theaters.